The subject invention relates to an IV catheter and introducer needle assembly that includes a needle shield that will safely shield the sharp distal tip of the introducer needle after the needle has been used to insert the catheter into a patient. Specifically, aspects of the invention are related to a needle and hub assembly for use with a catheter and introducer assembly having a needle shield, as well as a method of manufacturing such a needle and hub assembly.
Catheters, particularly intravascular (IV) catheters, are used for infusing fluid, such as normal saline solution, various medicaments and total parenteral nutrition, into a patient, withdrawing blood from a patient or monitoring various parameters of the patient's vascular system. Peripheral IV catheters tend to be relatively short, and typically are on the order of about two inches or less in length. The most common type of IV catheter is an over-the-needle peripheral IV catheter. As its name implies, an over-the-needle catheter is mounted over an introducer needle having a sharp distal tip. At least the distal portion of the catheter tightly engages the outer surface of the needle to prevent peelback of the catheter and thus facilitates insertion of the catheter into the blood vessel. The catheter and the introducer needle are assembled so that the distal tip of the introducer needle extends beyond the distal tip of the catheter with the bevel of the needle facing up away from the patient's skin.
The catheter and introducer needle assembly is inserted at a shallow angle through the patient's skin into a blood vessel. There are many techniques for inserting such a catheter and introducer needle assembly into a patient. In one insertion technique, the introducer needle and catheter are inserted completely into the blood vessel together. In another technique, the introducer needle is partially withdrawn into the catheter after the initial insertion into the blood vessel. The catheter is then threaded over the needle and inserted completely into the blood vessel.
In order to verify proper placement of the catheter in the blood vessel, the clinician confirms that there is flashback of blood in a flashback chamber. Once proper placement of the catheter into the blood vessel is confirmed, the clinician applies pressure to the blood vessel by pressing down on the patient's skin over the blood vessel distal of the introducer needle and the catheter. This finger pressure occludes or at least minimizes further blood flow through the introducer needle and the catheter. The clinician then withdraws the introducer needle, leaving the catheter in place, and attaches an appropriate device to the catheter. Such a device can include a fluid delivery device, a PRN, a deadender cap or a blood pressure monitoring probe. Once the introducer needle is withdrawn from the catheter, the introducer needle is a “blood contaminated sharp” and must be properly handled.
In recent years, there has been great concern over the contamination of clinicians with a patient's blood and a recognition that “blood contaminated sharps” must be disposed to avoid an accidental needle stick. This concern has arisen because of the advent of currently incurable and fatal diseases, such as Acquired Immunosuppressive Deficiency Syndrome (“AIDS”), which can be transmitted by the exchange of body fluids from an infected person to another person. Thus, contact with the body fluid of an AIDS infected person must be avoided. As noted above, if an introducer needle has been used to place a catheter in a blood vessel of an AIDS infected person, the introducer needle, via its sharp distal tip, is a vehicle for the transmission of the disease. Although clinicians are aware of the need to properly handle “blood contaminated sharps”, unfortunately in certain medical environments, such as emergency situations or as a result of inattention or neglect, needlesticks with a contaminated introducer needle still occur.
As a result of the problem of accidental needlesticks by “blood contaminated sharps”, various needle shields have been developed for use in conjunction with intravenous catheters. For example, needle shields have been designed to secure the tip of the needle within the shield after use, such as disclosed in U.S. Provisional Application Ser. No. 60/390,499 filed Jun. 20, 2002, Utility application Ser. No. 09/499,331, filed Feb. 4, 2000, U.S. Pat. No. 6,379,333, or U.S. Pat. No. 6,004,294, each incorporated herein by reference. Certain of these IV catheters with needle shields are operated by physically withdrawing the needle by hand through the catheter until the tip of the needle is within the shield. Specifically, the clinician grasps a hub attached to the needle and pulls it away from the catheter. Consequently, the operation of these intravenous catheters with needle shields depends, in part, on a sound connection between the needle hub and the needle. Generally, the needle hub-needle connection works for its intended purpose but could be improved in certain applications.